The design, evaluation, and management of immunisation programmes

The design, evaluation, and management of Immunisation programmes

This section covers:

The design, evaluation, and management of Immunisation programmes
Choices in developing an immunisation strategy

Immunisation

Aim of immunisation: to provoke immunological memory to protect individual against a particular disease.

Two types of immunisation:

Passive: Immediate protection with temporary source of antibody, e.g. Immunoglobulin (Ig's) and antitoxins
Active: longer term protection leading to the formation of antibodies

Types of vaccines

Live vaccine (attenuated strains which replicate in host)

Live vaccines include: Measles Mumps Rubella (MMR), oral polio, Bacille Camette Guerin (BCG), Yellow Fever, Live attenuated Influenza (LAIV) and Herpes Zoster vaccine.

Single dose often sufficient to induce long-lasting immunity
Act like natural infection
Long duration of immunity
Less stable: may revert to a virulent strain
Can cause disease in immuno-suppressed, (exception is HIV patients where do recommend, apart from BCG)

Inactivated vaccine (suspensions of whole intact killed organisms OR components of organism important in protection)

Inactivated vaccines include: Diphtheria Tetanus Pertussis (DTP), typhoid, Hepatitis B, flu, rabies, meningitis (ACWY, B) Hib, HPV

Stable
Unable to cause the infection
Need multiple doses and booster
Shorter lasting immunity

Contra indications to immunisation

Very few real contra-indicators - a confirmed anaphylactic reaction to a previous dose of the vaccine or to a component of the vaccine
Immuno-suppression (no live vaccines)

Vaccine failure

Primary: individual fails to make adequate immune response to initial vaccination
Secondary: individual makes initial adequate response, but then immunity wanes over time

Vaccination programmes

Development of a Vaccine Programme

Prior to designing a vaccine programme, must establish:

Is there a need for the programme? - does the disease cause a significant public health problem?
Is a suitable vaccine available that is safe and effective?

Aim of Immunisation Programme

To protect those at highest risk (selective immunisation strategy)

To eradicate, eliminate or contain disease (mass immunisation strategy)

Vaccination strategies

A. Selective Vaccination

Given to those at increased risk
Examples - for travel, e.g. Japanese B encephalitis, Typhoid, Hepatitis A; occupational, e.g. Hepatitis B, Anthrax, Varicella, MMR; At-risk groups
E.g. Hepatitis B vaccine for neonates born to Hepatitis B positive mothers, Pertussis vaccine for pregnant women to protect their infants from birth; chronic disease, e.g. Splenectomy - meningococcal, Hib, Pneumococcal; outbreak, e.g. Hepatitis A.

B. Mass Vaccination

Either

Eradication - Disease and its causal agent have been removed worldwide, e.g. small pox
Elimination - Disease has disappeared from one WHO region but remains elsewhere, e.g. polio
Containment - The point at which the disease no longer constitutes a 'significant public health problem', e.g. Hib

Issues in Vaccine Policy Decisions

Aim of programme
Cost of programme
Population accessibility
Cultural attitudes and practices
Facilities available for delivery

The need for a vaccination programme depends on:

Disease incidence
Age distribution of disease
Disease trends
Disease complications
Mortality
Population / cultural attitudes
Cost and benefit
Political expenditure
Vaccine efficacy and side effects
Availability and validity of delivering
Provision of trained primary care providers
Vaccine type

Development of a vaccination programme

Pre-license	Phase 1 studies	safety studies - in healthy adults
	Phase 2 studies	immunogenicity - in target population (n=100-120)
	Phase 3 studies	protective efficacy - in target population (large)
Post-license	Phase 4 studies	surveillance - to detect adverse events

Plus: pharmo-economic studies - Cost Benefit Analysis (CBA) / Cost Effective Analysis (CEA) (at phase 3)

Implementation of a vaccination policy

Recommendations for use of a vaccine/vaccine policy are based upon The Joint Committee of Vaccination and Immunisation (JCVI) expert opinion after reviewing all the available evidence
The JCVI is an independent expert advisory committee whose role is to advise UK public health departments on matters relating to communicable diseases, preventable and potentially preventable through immunisation
   - choice of policy - mass or selective
   - publish recommendations in ‘Immunisation against infectious disease’
   - commonly referred to as the “Green Book”
   - license vaccine and batch release
   - procurement of vaccine

Commissioning delivery

Media campaign, and start giving vaccinations.

Factors associated with low immunisation coverage

socio-demographic variables
deprived, inner city living
mobile families
birth order, large families
children with chronic illnesses
ethnicity
personal variables
parents
professionals
health service variables - generally good in the UK, but be aware of some limitations
poor co-ordination (private and public sectors)
unclear responses
access to guidelines and policies

UK initiatives leading to improved coverage in 1990s

1986: district immunisation coordinator appointed
1987: rapid monitoring and feedback of coverage data - COVER statistics
1988: national guidelines on immunisation
1990: accelerated immunity schedule
1990: GP contracts - financial incentives
1992: parent-held records/Personal Child Health Record often referred to as the Red book
National vaccination campaigns - intermittent (e.g. MMR/Hib)

Other:

Opportunistic delivery
Specific immunisation clinics
Targeted information campaigns
UK immunisation service is considered a world example
Initiated by birth notification on 'Child Health System'
Child Health Information Services (CHIS) computer generates automatic letters inviting children for vaccination, and ensures GP call and recall for immunisation

Vaccine Coverage

COVER (Cover of Vaccination Evaluated Rapidly)

In the UK since 1988 computerised child health records contain vaccination details of all children resident in the area. These are completed each time a vaccine is given by a healthcare professional.

Vaccine information is collected by PHE Centre for Infectious Disease Surveillance and Control (CIDSC) every 3 months from local Child Health Computer Systems detailing the number of children who have completed the vaccination schedule at 1, 2 and 5 years of age.

These data are promptly fed back to local level, creating the opportunity to improve coverage and to detect changes in vaccine coverage quickly

Public Health England also collect data via the Immform system to assess coverage of vaccinations delivered to adolescents and adults, e.g. HPV, pertussis for pregnant women, seasonal influenza. These are largely derived from an automated extraction of data held on GP systems but also includes some manual recording for vaccines delivered outside of primary care, e.g. HPV vaccine in schools. The Immform platform also provides vaccine-ordering facilities for the NHS

Uses

Detect change rapidly and monitor trends in uptake
Look for pockets of poor coverage
Estimate vaccine efficacy
Measure impact and success of a vaccination campaign
Evaluation of Vaccine Programmes
Disease incidence
Susceptibility
Vaccine Coverage
Adverse events and vaccine safety

Monitoring Adverse Events and Vaccine Safety

Committee on Safety of Medicines (CSM) advises the Medicines and Healthcare products Regulatory Agency (MHRA) on safety, quality and efficacy of vaccines
MHRA responsible for Yellow Card Adverse Drug Reaction reporting system
Yellow Card reports can signal possibility that a product may be associated with certain risks. These can then be investigated further to decide whether a side effect is truly from a vaccine or not.

United Kingdom Routine childhood Immunisation schedule 2016

All children starting the immunisation programme at 8 weeks of age will follow the schedule below.
When to immunise	What is given	Vaccine and how it is given
Eight weeks old	Diphtheria, tetanus, pertussis (whooping cough), polio, Haemophilus influenzae type b (Hib) and hepatitis B (DTaP/IPV/Hib/HepB)	One injection (Infanrix hexa)
	Pneumococcal (13 serotypes) (PCV)	One injection (Prevenar 13)
	Meningococcal group B (MenB)	One injection (Bexsero)
	Rotavirus gastroenteritis	Oral suspension in pre-filled oral applicator (Rotarix)

12 weeks old	Diphtheria, tetanus, pertussis, polio, Hib and hepatitis B (DTaP/IPV/Hib/HepB)	One injection (Infanrix hexa)
12 weeks old	Rotavirus	Oral suspension in pre-filled oral applicator (Rotarix)

16 weeks old	Diphtheria, tetanus, pertussis, polio, Hib and hepatitis B (DTaP/IPV/Hib/HepB)	One injection (Infanrix hexa)
	Pneumococcal (13 serotypes) (PCV)	One injection (Prevenar 13)
	Meningococcal group B (Men B)	One injection (Bexsero)

One year old (on or after the child's first birthday)	Haemophilus influenzae type b, Meningococcal group C (Hib/MenC)	One injection (Menitorix)
	Measles, mumps and rubella (German Measles) (MMR)	One injection (MMR VaxPRO²or Priorix)
	Pneumococcal (PCV)	One injection (Prevenar 13)
	Meningococcal group B (Men B Booster)	One injection (Bexsero)

Two to Eight years old¹ (including children in reception class and school yers 1-4)	Influenza (each year from September) Live attenuated Influenza vaccine (LAIV³)	One pre-filled nasal spray (Fluenz Tetra²)

Three years four months old or soon after	Diphtheria, tetanus, pertussis and polio (DTaP/IPV)	One injection (Infanrix-IPV or Repevax)
Three years four months old or soon after	Measles, mumps and rubella (MMR) Check first dose given)	One injection (MMR VaxPRO²or Priorix)

Girls aged from 12 to 13 years old	Cervical cancer caused by human papillomavirus (HPV) types 16 and 18 (and genital warts caused by types 6 and 11)	Two injections 6-24 months apart (Gardasil)

Fourteen years old (school year 9)	Tetanus, diphtheria and polio (Td/IPV) Check MMR status)	One injection (Revaxis)
Fourteen years old (school year 9)	Meningococcal groups A, C, W and Y disease (Men ACWY)	One injection (Nimenrix or Menveo)
^{1. Age on 31 August 2017. 2. Contains porcine gelatine. 3. If LAIV (live attenuated influenza vaccine) is contraindicated and the child is in a clinical risk group, use inactivated flu vaccine.} The Routine Immunisation Schedule https://www.gov.uk/government/publications/routine-childhood-immunisation-schedule Vaccine policy changes in England are communicated in joint letters from DH, PHE and NHS England (formerly CMO) and ‘Vaccine Update’ (a monthly newsletter from PHE)